In very rare cases, cats can develop a sarcoma at the injection site, but not vaccinating is much more dangerous. Veterinary oncologist Dmitry Trofimtsov told Gazeta.Ru about this.
“It has been shown that cats sometimes develop sarcoma at the site of vaccine administration. But this happens very rarely, about three times out of a hundred thousand. Dogs have certain types of papillomavirus that increase the risk of certain types of cancer, such as squamous cell skin cancer. The virus is transmitted to the puppy from the mother, as well as through saliva when sharing bowls and toys. Humans also have papillomaviruses, including oncogenic ones, but exchange between dogs and humans is impossible: infections are species-specific,” Trofimtsov explained.
The doctor added that due to the risk of sarcoma, some vaccines are recommended to be administered not at the withers, but at the knee crease or at the base of the tail: this way they are easier to treat. One of the functions of the immune system is to fight cancer. Trofimtsov noted that the weakened immunity of an unvaccinated animal due to viruses can increase the risk of developing cancer, so you should not refuse vaccination.
Read more about the prevention of cancerous tumors in dogs in the Gazeta.Ru article .